冲刷条件下长江枝城至沙市河段床沙级配模拟

三峡水库蓄水运行后,清水下泄,坝下游河道遭受持续冲刷,以致产生了不平衡的输沙问题,而床沙级配的变化又是其中不可忽视的原因之一。结合2015年7~9月长江枝城至沙市河段的冲刷过程实测资料,依据断面地形测量计算的冲淤变化结果以及河段进出口断面的悬移质级配成果,采用韩其为理论公式,对该河段的床沙级配进行了数值模拟计算,并运用实测数据对模拟的结果进行了验证。验证结果表明,在冲刷条件下,该方法基本上可以预测长江枝城至沙市河段沿程床沙的级配变化情况。该结论可为验证三峡水库坝下游的不平衡输沙理论提供实例证据。

Numerical simulation of bed load gradation at Changjiang reach from Zhicheng to Shashi under erosion condition

After the Three Gorges Reservoir was put into operation, clear water scours the downstream channel continually, and the imbalanced sediment load transport occurs, in which the variation of bed load gradation is an important cause. According to the surveyed erosion data from Zhicheng to Shashi from June to September, 2015, we obtained the erosion variation by the geography data and the suspended load gradation at the inlet and outlet cross-sections, based on this we carry out numerical simulation on the bed load gradation by Hanqiwei formula, and verify the simulated results by the measured data. The results show that the presented method could predict the bed load gradation variation along the reach under erosion condition, which could provide support for the verification of the imbalance load transport in downstream reach of the Three Gorges Dam.